Many electrical circuits or electronic devices require a conditioning of a signal to obtain a conditioned signal that satisfies certain predetermined requirements as to e.g. signal level of the signal. For example, a transducer (e.g. a loudspeaker) may perform optimally within a certain range of the signal level delivered to the transducer. For this purpose, amplifier circuits and amplification methods may be used that receive an input signal, amplify the input signal by a gain factor to obtain an output signal, and deliver the output signal to the transducer of the electronic device for rendering.
The amplifier circuits and amplification methods may make use of automatic gain control schemes in order to determine the gain factor applied to the input signal. The gain factor may be determined such that the output signal has a predetermined signal level. The present document addresses the particular aspect of electronic devices comprising transducers (e.g. loudspeakers) which may be operated in a hands-free mode. In this context, it is desirable to determine the gain factor such that the loudspeaker and cabinet acoustic distortions and mechanical resonances are reduced (e.g. minimized). Furthermore, the gain factor should be determined such that the overall signal level of the output signal at the loudspeaker is increased (e.g. maximized). In addition, electronic devices (e.g. cordless or mobile telephones) typically comprise an echo canceller. The gain factor should be determined such the acoustic echo canceller performance is improved.